Hypodermic syringe



Nov. 7, 1944. A. E. SMITH HYPODERMIC SYRINGE Filed Jan. 4, l94l iJi . INVENTOR. A. E. SMITH Patented Nov. 7, 1944 *1? 275;:

S ENT Q E 1 nrronERMIo SYKINGE Arthur E. Smith, Los than; Calif. Application January 4, 1941, Serial No. 373,129 1 01am. (ohms-21s).

IThiS invention relates to hypodermic syringes. The general object of the invention is to provide a novel hypodermic syringe of the type used by dental surgeons and :others particularly for the injectionof local anesthetics. i

A further object of the invention is to provide a syringe having, a novel ampule-centering means therein.

Another object of the invention is to provide a syringe including a novel front end member for conducting the injecting fluid from the barrel of an ampule.

A further object of the invention is to provide a syringe including a novel co-acting plunger and sliding ampule cork, which are so shaped as to reduce the pressure of the frictional engagement between thesliding cork and the ampule.

Other objects and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing wherein:

Fig, l is a central sectional view through a syringe and ampule embodying the features of my invention.

Fig. 2 is a fragmentary, central sectional, view through the ampule.

Fig. 3 is a section taken on line 3-3 of Fig. 2.

Fig. 4 is a fragmentary sectional view with parts in elevation showing the position assumed when the syringerear member is first inserted in place.

Fig. 5 is a fragmentary; enlarged, sectional, detail showing the position assumed when the ampule is in place in the syringe and ready for use.

Fig. 6 is an enlarged sectional view of the stopper member showing its general shape when the plunger is depressed.

Fig. 7 is a central sectional view through the ampule and syringe showing the position assumed by the parts after the contents of the ampule have been injected.

The construction described herein is particularly useful in syringes wherein it is desired to maintain a drug in a compartment sealed off from the solvent for the drug. For example, since novocain deteriorates when in solution, a novocaln tablet or powder may be placed in the chamber in a closure and the solvent for the novccain placed in the main body of a container in which the closure is placed. When the disk is forced out of the recess, the novocain will enter into the solventproviding the desired fresh solution. g

Referring to the drawing by reference characters. I have shown my invention as embodied in a syringe which-is indicated generally at In. As shown the syringe includesa barrel ll, having internal threads l2 at the, front end and with a front member l3. threadedly engaging the threads 12. The front member I3 is provided with a tube M which projects into the barrel'and has a pointed tip l5 thereon with, a shoulder l6 adjacent the'base end of the tip; The tube I4 includes openings I! which pierce the shoulder l6 and are arranged at anacute angle relative to the axis of the tube l4. The tube l4 also includes openings l8 which are arranged in opposed relation. The construction of tip I5, shoulder i6 and openings l1 and I8 is such that there is no likelihood of communication being obstructed between the interior of the ampule and the interior of the tube l4.

Mounted on the front member I3 I show a needle I!) which is of the double-ended type and which includes an inner end 20 projecting into the tube l4 and a front pointed end 2|.

The rear end of the barrel H is internally threaded as at 22 and receives a cap or closure member indicated generally at 23. This cap receives a collar 24 which is shown as secured thereto by a pin 25. The collar is externally threaded as at 26 to engage the threads 22.

A telescoping or segment member 21 slides within the collar 24 and is apertured as at 28 to receive a shank 29 of a plunger which includes a push member 30. The member 21 includes an external flange 3| which engages an internal flange 32 on the collar 24 to limit the movement of the member 21. A

The member 21 has an enlarged head 33 thereon which slides in a counterbored end portion 34 in the outer portion of the barrel H. The head 33 is urged inwardly by a spring 35 disposed about the plunger shank 29.

The head 33 is recessed as at 36 to receive an enlarged head 31 on the plunger shank 29 and is'inwardly bevelled as at 38 to engage and act as a guide for the upper end of an ampule indicated generally at 39. The upper end of the ampule projects above the shoulder 40 formed at the inner end of the counterbored portion 34. The head 31 is cupped as at 4| and is adapted to' engage an upper stopper 42 in the ampule 39.

The stopper 42 is preferably made of flexible rubber or similar material and includes a skirt 43 and an end diaphragm portion 44. The stopper'may include a peripheral groove 45 in which a lubricant, such as paraffin, may be placed.

The ampule 39 includes a lower stopper 46 of rubber or similar material which includes an outer flange 41 abutting the end of the ampule. The stopper 46 further includes an upper circular trap door closure member 48 having an arm-- ately grooved periphery 49 sealingly engaging a correspondin bead 50 in the stopper. The stopper 46 is recessed below the closure 48 to form a chamber 5| to receive a medicament 52. The stopper 46 is counterbored as at 53 to receive a rubber plug member 54 which includes an easily rupturable diaphragm 55 and an end recess 56.

In use the ampule 39 is positioned within the barrel H and the cap 23 is screwed down. The length of the barrel is such that just as the threads engage, the pointed tip l5 of the tube l4 ruptures the diaphragm 55. The tip then moves inwardly unseating the closure member 48 and allowing the medicament 52 to pass into the vehicle within the ampule.

To discharge the contents of the ampule, the plunger 29 is depressed, whereupon the cupped head 37 engages the stopper 42 causing the latter to assume the shape. shown in Fig. 6. It will be seen that the plunger head being cupped, permits the adjacent end of the stopper 42 to move somewhat into the cupped portions thus reducing the pressure on the adjacent side wall portion of the stopper and reducing the pressure between the stopper and the ampule wall and thus facilitate movement of the stopper.

Further movement of the plunger ejects the fluid of the ampule and brings the parts into the relationship shown in Fig. 7.

I claim:

In a hypodermic syringe, a hollow barrel having an ampule therein, a spring urged rear member slidable within said barrel, a plunger shank passing through said rear member, a head on said plunger, a resilient piston stopper in the rearrend. of saidampule, the head of said plunger being adapted to engage the end of said stopper, a second stopper in the front end of the ampule, said second stopper havin a displaceable portion, a front member secured upon said barrel, said from member including a tube extending into said barrel, said tube being adapted to receive the upper end of a double pointed hypodermic needle, said tube being closed at its forward end and having a tip projecting beyond the closed end, there being an inwardly directed, forwardly facing shoulder at the junction of the tip and tube, said tip being adapted to engage said second stopper displaceable portion, said tube including openings which extend through said shoulder to the interior of said tube.

ARTHUR E. SMITH. 

